Shirk is an Arabic word which means a partnership. While it is termed in Islamic theology as act of associating partnership with Allah. It is the act of rendering to a creatures respect, honour, obedience or adoration that is only due to the creator (Allah) alone. It is an unforgivable sin which all Muslims should stay away from. Allah said in following verses.
a.) "Verily Allah forgive not that a partner should be ascribed unto Him. He forgives all other (sins) to who He wills. Whose ascribes partners unto Allah has indeed invented a tremendous sin" (Q4: 48)
b.) "......So shan the filth of idol (Worship)  and shun lying speech. Turning unto Allah (only), not ascribing partners unto Him, for whose ascribes partner unto Allah, it is as if he had fallen from the sky and the birds had snatched him or thew wind had blown him to a far-off place." (Q22: 30-31).

                                                              Types of Shirk

It can be observed in these verses that Shirk is highly condemned by Islam. It is imperative for us to know the various types of Shirk. They are as follows: Idol worship, Worship of natural phenomena, ancestors and hero worship, atheism, trinity, humanism, superstition, witch craft e.t.c.

                      Idol worship and the worship of natural phenomena  (i.e. heavenly bodies).

Idol is an object which is either created or carved by man or nature in which human being believe of having supernatural power such as objects includes among others statue or picture of a human being or animal form, springs, natural rocks, trees, rivers while heavenly bodies include Moon, Sun, Stars and planets.
                       Muslim should avoid the act of worshipping any of the above mentioned objects because they were created beings like oneself. The same things go to all personifies creatures such as a moon, goddess, sun god, venus (God of love), mars (god of water) e.t.c. and even the all of superstate such as good stars, lucky colors e.t.c are all forms of shirk. Allah mentioned in the Qur'an that all the heavenly bodies are also created things in  the following verses:
"And of His patient are the night and the day and the sun and the moon. Adore not the sun not the moon, but adore not the sun nor the moon, but adore Allah Who created them if it is (in truth) Him whom you worship." (Q41:37)

                                                         Ancestor and hero worship.

Ancestor worship: Human beings especially Africans and China believed the spirit of some of their ancestors, usually back to the World in their society to observe the activities of their descendants such society visits the people and spiritual shrines where they believe that the spirit of such ancestors are present. Allah condemned the act of the worship of ancestors in the following verse.
'There is no god Except Him'. He grant life and gives death, your lord and lord of your fore fathers" (Q44:8).
Hero worship: This is the believe of human beings that a special divinity is given to a certain leader, saint or prophet, such  personality among others includes Jesus (the son of God by ancient Egypt), Mi (the acdalmed son of God by ancient Persian) e.t.c. The believers in this divinity have the believe that such personalities are endowed with divine power.

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